Today, more emphasis is being placed on quality of life assessment in the evaluation of the efficacy of medical care.[1,2] A new study, described below, along with other international quality of life studies, suggests that physicians and their patients may place different values on different health outcomes of treatment, depending on socioeconomic status and cultural milieu.
For some patients, the chance of extending survival may override all other considerations, while for others, a shorter life with higher quality may be more important. A new research method, known as quality assessment (described below), now allows the patient's value system to be quantified in such a way as to help the patient and physician come to a decision about treatment of advanced cancers.
How Patients View Quality of Life
The way patients view their quality of life depends not only on the physical presence of a disease but also on the psychological and social responses to symptoms caused by that disease. Cancer is an example of a chronic disease whose treatment and prevention goals are to extend life expectancy while improving patient quality of life.
Patients' experience and evaluation of their cancer are known to vary significantly according to patient characteristics such as age, gender, ethnicity, and socioeconomic status. Similarly, an individual's value and interpretation of quality of life is largely determined by personal, interpersonal, and cultural aspects that make up a person's values, expectations, and perceptions.
Because of the effect of different cultural backgrounds on the patient's perception of quality of life, recent studies have focused on cross-cultural assessments of the impact of diseases. The two main types of international quality of life studies are described below, with examples of each.[7-11]
International Quality of Life Studies
The first type of international quality of life study evaluates comparisons of quality of life assessments from subjects in different countries. These studies show that performance is consistent within broad cultural groups representative of regionally and economically similar countries.
A review of combined data from several similar studies showed that participants from up to 17 different countries gave similar ratings to most items relating to various health states. The largest differ-ences were evident between ratings given by the general public and those of physicians.
In these studies, there is relatively more agreement for items that express purely physical states and less agreement for items that reflect socioemotional states that are more likely to be affected by cultural values.[7,8]
The second type of study compares opinions of people from two or more countries on a given subject (eg, attitudes toward cancer). These studies have found that within a broad cultural group, opinions do not vary significantly between countries. For example, in one such study, English, Italian, German, and Swedish speaking breast cancer patients showed concordance in their opinions toward health states associated with cancer.
Large differences have been observed, however, in the opinions of subjects from Eastern and Western cultures. Cancer patients from the United States, for example, were shown to have different attitudes toward their disease than patients from Egypt and India,[10,11] findings attributed to differing cultural perspectives.
While it is important to qualitatively evaluate patient attitudes toward cancer, use of additional quantitative data can enhance comparisons between groups of patients. Such information, however, is often difficult to obtain. One method that has been widely used to quantitatively interpret patient attitudes toward various aspects of cancer is utility assessment.
A utility score is a quantitative measure of the strength of a person's preference for a specified health outcome. Utility scores are measured on a scale of 0 to 1, in which 0 represents death and 1 represents perfect health.
Typically, utility scores are determined by asking a series of questions about a health state to find out how much a person would be willing to risk to improve that health state. For example, patients may be asked how much time they would give up to improve quality of life. The point of indifference occurs when the patient rates shortened life expectancy with perfect quality of life the same as longer life expectancy with lower quality of life.
In an effort to assess the utility of health states related to cancer and its treatments, many studies have looked at responses to utility instruments from oncologists on behalf of their patients.
In one case study, 33 physicians from 14 different (primarily European) countries were presented with scenarios of alternative health states associated with cis-platinum chemotherapy. The physicians were asked to estimate patient prefer-ences for the likely health states associated with the cancer chemotherapy and chemotherapy-related toxicities. This is one of the first studies to consider international utility assessments.
The toxicities examined in this study were neurotoxicity and nephrotoxicity, which are the most common and most severe side effects of cis-platinum chemotherapy. For each scenario corresponding to a particular toxicity, five health states of increasing severity were defined for the physician respondents. For each health state, the physicians were asked to respond to a sequence of questions to identify the lowest amount of full-quality life-months a typical patient would consider to be comparable to living one year in the defined state.
The responses were then converted into utility scores by dividing the number of months indicated by the physicians for each health state by 12 months. For example, if the physician indicated that 11 months of full-quality life was equivalent to one year with numbness due to mild neurotoxicity, the utility for that health state was 11/12 or 0.92.
In other words, the higher the utility score, the more the physician feels that the health state is an acceptable trade-off between benefit (greater survival with treatment) and risk (side effects).
Participating physicians were categorized into two subgroups based on the Gross Domestic Product (GDP) and health care expenditure per capita of the countries in which they were practicing (Table 1).
Comparison by Country's GDP
The 22 physicians from countries in the "higher GDP" group represented Germany, Denmark, Finland, the United Kingdom, Italy, Spain, Greece, and Portugal. The 11 physicians from countries in the "lower GDP" group represented the Czech Republic, the Slovak Republic, South Africa, Hungary, Argentina, and India. Physician responses were compared for the two toxicities both within and between the two groups.
Worse health states were consistently associated with lower utility assessments. As utility scores decreased, the range of scores became wider, indicating less agreement among respondents.
The mean responses were calculated for the two subgroups of physicians from countries with higher and lower GDPs (Table 2). Within each subgroup, the responses tended to be similar, especially for the mild health states (95% confidence intervals were less than ± 0.05).
However, physicians from the higher GDP countries valued individual health states with lower utility scores (implying a less favorable view of the particular health state) than those given by the physicians from the lower GDP countries.
For example, physicians from higher GDP countries viewed mild neurotoxicity with cis-platinum therapy as having a score of 0.83 vs 0.91 given by the physicians from lower GDP countries.
This study has important results with possible applications to clinical practice. First, the data provide empirical support for including health status and utility assessments when considering chemotherapeutic options. Second, there were significant international variations between the two groups. Thus, within broad cultural categories, there is likely to be some general consensus on preferences for particular health states, yet cultural groups are likely to view illness differently.
International quality of life studies are important in evaluating cancer treatments. While previous studies have focused on past and present quality of life, few have included utility assessments, which incorporate expectations for quality of life in the future.
The utility assessment study discussed here shows that subjects from countries with higher per capita GDP have markedly different evaluations of health states than do subjects from countries with lower GDPs. Cultural differences in attitudes need to be understood to make the most appropriate care and treatment decisions for patients in different countries.